It is becoming increasingly popular to purposely introduce particulate or pulverulent matter into a tire to affect the tire characteristics. This application involves introducing a powder of specific composition into the tire to dynamically "balance" the tire and to reduce radial and lateral force variations found within a tire under varying load conditions. This method is taught and described in applicant's prior U.S. Pat. No. 5,073,217 and applicant's copending application Ser. No. 08/184,735, both of which are herein incorporated by reference. The particulate composition is sold by International Marketing, Inc. under the trademark "EQUAL.RTM.."
These various powders and substances may cause loss of air through the tire valve core, especially upon the checking of tire air pressure. The small size of the particles allows the particles to enter the valve core assembly and these particles may adversely affect the valve core components or their operation. Furthermore, it is desirable to prevent these installed substances from escaping the tire. By preventing the escape of the pulverulent powder, the powder does not enter the atmosphere and does not need to be replenished when the tire is re-inflated.
The EQUAL.RTM. tire balancing formula is often placed within new tires before the valve core is installed and before the tire is inflated. However, to introduce particulate compositions into an installed tire, it saves time and effort and is generally desirable to introduce such substances directly into a tire which already has a tire valve installed and which may already be partially or fully inflated. This is accomplished by introducing the powder or particulate matter directly into the valve under pressure such as in combination with compressed air to force the powder into the interior of the tire. A valve stem containing a simple screen or mesh to prevent valve core blockage upon tire air pressure checks does not allow such particulate matter to be introduced into the valve core seat because the screen or mesh blocks the particulate matter.
Also, it is not uncommon for a tire to contain other particulate matter such as dust, dirt, and as a consequence of use whereby particles of rubber become dislodged from the interior bead of the tire and freely move about the interior of the tire when the tire is in use. Over time, a large number of such particles may be found in any tire. It is not uncommon for these particles to enter into the tire valve core and prevent the valve from fully closing resulting in an air leak. This is especially likely to occur when air is released from the tire as the flow of air exiting the valve naturally draws the particles into the valve core.